1. Field of the Invention
The present invention relates in general to a sewing machine which stitches cloth, leather and other material by means of an eye-pointed needle, and more particularly, the present invention is concerned with a sewing machine of a type having a folder by which a tapelike material is continuously folded into two before it is stitched by the needle.
2. Description of the Prior Art
In order to clarify the task of the present invention, one conventional sewing machine of the above-mentioned type will be outlined in the following with reference to FIGS. 5, 6 and 7 of the attached drawings.
Referring to the drawings, particularly FIG. 5, there is shown an essential part of the conventional sewing machine 100 which generally comprises an eyepointed reciprocating needle 12, a liftable presser 14 for putting a suitable weight upon a tape-like material 16 and a carrier (not shown) located below the presser 14 for intermittently carrying the material 16 forward, that is, toward the needle 12. The sewing machine 100 is provided with a folder 18 by which the tape-like material 16 is continuously folded into two parts 16a and 16b before it is stitched by the needle 12. As is seen from FIG. 5, the holder 18 is constructed of a bent-up hollow plate member which comprises an equilateral triangular major portion 18a having an elongate inlet slot 20, an inequilateral triangular upper portion 18b extending along the upper side of the major portion 18a and having an outlet slot 22a, and an inequilateral triangular lower portion 18c extending along the lower side of the major portion 18a and having an outlet slot 22b. As may be understood from FIG. 8, the outlet slots 22a and 22b are joined at their one ends to form a compressed U-shaped outlet which faces toward the needle 12. The major portion 18a is formed at its one wall with a longitudinally extending slot 24 which is exposed to the hollow of the major portion 18a. During sewing operation of the sewing machine 100, the tape-like material 16 is continuously fed into the folder 18 from the inlet slot 20 and gradually folded into two parts during its passage through the hollow allowing the U-shaped outlet (22a, 22b) of the holder 18 to continuously draw out a twice-folded material (16a, 16b) which is to be stitched.
ln order to set the tape-like material 16 to the folder 18 for preparation of sewing, a leading end of the material 16 is manually thrusted into the folder 18 to such a degree that a part of the inserted material 16 is exposed to the slot 24 of the major portion 18a. Then, a pin-mounted tool 26 (see FIG. 5) is manipulated to stick the pin into the inserted material 16 through the slot 24. Then, the tool 26 is moved forward, that is, toward the U-shaped outlet of the folder 18 with the pin catching the material 16, until the twice-folded leading end (16a, 16b) of the material 16 projected from the outlet comes to the position of the needle 12. Then, the tool 26 is removed and the sewing machine 100 is operated for continuously stitching the twice-folded parts 16a and 16b of the material 16 drawn from the folder 18.
However, the manual work for setting the material 16 to the folder 18 is difficult or at least troublesome. In fact, the setting has required a skilled technique.